This invention relates to a technology for extracting data from a database, and more particularly, to a technology for extracting sorted data.
In recent years, with an improvement in tools for collecting an enormous volume of data relating to corporate activities, a business data analysis in which an on-site person in charge uses an enormous volume of accumulated sales data for analysis is becoming widespread. In the business data analysis, the analysis is performed stepwise as in hypothesis planning/trend analysis/factor analysis.
In the business data analysis, the on-site person in charge repeats the hypothesis planning and the trend analysis a large number of times after trial and error, which necessitates extraction of an enormous volume of data. Therefore, such an enormous volume of data is managed by the database for effective processing thereof.
In a database system for processing the enormous volume of data, data to be analyzed is stored in a plurality of tables. To extract data, the data stored in the plurality of tables is joined, and the data that satisfies a condition designated by an analyzer is extracted.
Therefore, for a speedup of the processing for extracting such data, Out-of-Order Database Engine has been developed as disclosed in Japanese Patent Application Laid-open No. 2007-34414. Out-of-Order Database Engine enables the speedup of the extraction of data by issuing data read requests to a secondary storage device for storing data in a multiplexing manner.
On the other hand, in the business data analysis, it is necessary to extract necessary data from the enormous volume of data accumulated in the trend analysis and the like and to sort the extracted data in a designated order to facilitate the analysis. As Out-of-Order Database Engine, US 2010/0211577 A1 discloses a technology for sorting data at high speed with respect to a column for which an index has been created.